The five-year contract is for stockpile rehandle services. Underground mining contractor Byrnecut has established a new mine egress via the base of the depleted openpit, which will shorten underground haul cycles. Material will be picked up from the new pit stockpile area for transfer to the processing plant.

Thiess has been working at Prominent Hill since 2006, providing openpit mining services.

CIMIC executive mining and mineral processing and Thiess managing director Douglas Thompson said the company had a strong working relationship with OZ.

"Since we first began work with the team 12 years ago, we've focused on understanding OZ Minerals' priorities, and have continually challenged ourselves to provide flexible services, delivering operational excellence and long-term value to our client."

Thiess will begin work next month.

CIMIC (ASX: CIM) shares last traded at A$42.40, valuing the company at $13.75 billion.